1. Field of the Invention
The present invention relates to an ink tank, and, more specifically, to an ink tank to be employed to an inkjet printing apparatus.
2. Description of the Related Art
Along the advance of image quality of printing in recent years, commonly employed in inkjet printing apparatuses is a method of increasing the number of ink colors used for printing in order to improve the image quality targeting for photographic image quality. A method of providing multiple tanks is widely used in a desktop printing apparatus, the tanks prepared for different colors and being independently detachable. Such a configuration causes an increase in the number of ink tanks, whereby the frequency of tank replacing operations by a user is increased. Moreover, as the ink tanks are provided independently, the wall thickness of each of the ink tanks has a great influence on the size of the printing apparatus.
Accordingly, from the viewpoint of user friendliness and of downsizing printing apparatuses, ink tanks which are configured to integrate ink containers for multiple colors have been proposed.
In order to achieve stable ink supply, an ink tank provided with multiple ink supply ports corresponding to ink containers for multiple colors, needs to be attached so that the respective ink supply ports are securely fixed to a holder of the apparatus. To achieve such secure attachment, proposed is an attachment mechanism including a mounting member called a latch lever as disclosed in Japanese Patent Laid-Open No. 08-058107. Such an attachment mechanism has been applied to many types of ink tanks because the mechanism enables simple attachment and detachment of the ink tanks.
In addition, proposed is a configuration to allow an ink tank to store predetermined information concerning the ink tank such as the colors of inks contained therein, and thereby to fulfill a required function according to the information. Japanese Patent Laid-Open No. 11-291518 discloses a configuration of an ink tank including a board mounted with an information storage element and means for electrically presenting stored information. A printing apparatus is configured to read the information at the time of attaching the ink tank to perform operation control, thereby being able to achieve fine printing outputs at any time. Japanese Patent Laid-Open No. 2006-116786 discloses a configuration to establish both secure connection in an ink supply system and a fine state of connection in an information communication system between an ink tank and a printing apparatus.
FIGS. 14A and 14B are schematic cross-sectional views for explaining the configuration and operations of an ink tank attachment mechanism disclosed in Japanese Patent Laid-Open No. 2006-116786.
The ink tank includes a board 1024, which is provided with a storage element being able to store information and a contact section for communicating the information with the body. Moreover, an ink tank holder section of the body, to which the ink tank is attached, includes a contact unit 1103 provided with a contact pin, which is to be in contact with the contact section provided to the board 1024 of the ink tank. This contact unit 1103 is movable in the y directions as shown in FIG. 14A, and is biased to the position indicated in FIG. 14A by use of a spring 1017 when the ink tank is not attached.
The ink tank is provided with a fitting section 1101 for position alignment in order to accurately position the contact section for communicating the information. On the other hand, a corresponding engagement section 1102 for position alignment is provided to an attachment section (a holder) of a printing apparatus. The fitting section 1101 provided to the bottom face of the ink tank forms a substantially triangular concave section which is engageable with the engagement section 1102 of the holder.
When the ink tank is attached to the holder, the tip end of the engagement section 1102 firstly touches an end of a slope 1104 of the fitting section 1101 located on the bottom face of the ink tank, as shown in FIG. 14A. In this state, when a user presses down the upper end of the ink tank, the tip end of the engagement section 1102 slides on the slope 1104 of the fitting section 1101 and accordingly enters the concave section that forms the fitting section 1101.
When mechanical attachment is completed, electric contact sections of both of the constituents, namely, the contact section of the board 1024 of the ink tank and a contact pad included in the contact unit 1103 of the holder provided to the apparatus, come into contact with each other, thereby enabling electric connection.
Here, in terms of a configuration at the connection part between the ink tank and the printing apparatus, a contact section for an ink supply system and a contact section for an information transmission system are separately provided. Moreover, the constituent on the holder's side for the contact section for the information transmission system is rendered movable. This configuration makes it possible to establish a fine state of connection between the ink supply system and the information transmission system.
However, sealing members made of rubber are provided either around ink supply ports or around ink receiving sections on the holder's side to be connected to the ink supply ports. The sealing members are provided in order to suppress ink leakage and ink evaporation, when the ink tank is attached. The ink tank receives a reactive force from the sealing members at the time of attachment, whereby being attached while being sometimes tilted from side to side (in an orthogonal direction to FIGS. 14A and 14B). Occurrence of such a tilt of the ink tank may lead to a failure in smooth engagement of the contact section for the information transmission system at the beginning. Accordingly, there are problems that the attachment property of the ink tank may decrease, and that electric connection may be made inaccurately.
While these problems apply also to the case of an ink tank configured to contain a single-color ink, the problems are even more critical in the case of an ink tank configured to contain inks of multiple colors. This is because the ink tank configured to contain the inks of multiple colors include multiple ink supply ports disposed on the bottom face of the ink tank, and, accordingly, the reactive force caused by the rubber are increased at the time of attachment. In addition, without careful arrangement of the positions of the multiple ink supply ports, the ink tank may be attached while tilting or rolling from side to side.